Data transfer in wireless local area networks between a first and second communicant may involve a first standardized data transmission rule or format and transmission and/or reception on electromagnetic signal paths of information elements with variant element formats. The information elements in this case may include an element identification part, a length statement part and an information part. The element identification part has a permissible value range from which a first standardized value of the element identification part identifies the information element as a first information element. The information part of the first information element contains parameters which relate to the data transmission of the communicant in accordance with a first data transmission rule as the transmitter. A receiving communicant stores the parameters which relate to the transmitting communicant in order to set the data transmission in the reply to the transmitting communicant. On identification of a value of the element identification part outside the permissible value range, each of the communicants, as the receiver determines the length of the information part from the length statement part, and jumps over the information part corresponding to the determined length.
A communication device for data transmission in wireless networks may be connected as the first communicant in such networks to a second communicant via electromagnetic signal paths. The communication device has at least one transmitting unit. In this case, a first data transmission rule (which defines first information elements comprising an element identification part, a length statement part and an information part) is implemented in the communication device and defines a permissible value range for the element identification part.
The importance of wireless networks has increased continuously in recent years. Their usage capabilities appear to be unlimited. The simplest option is to use two or more hosts (communicants) with wireless network cards in a so-called ad-hoc network.
If it is intended to connect the wireless network (WLAN) to a wire-based local area network (LAN), an access point (AP) is required. A network structure such as this is also referred to as a distribution system (DS).
An access point (first communicant) forms a radio cell with at least one individual station (second communicant).
The increase in coverage is achieved by additional cells with two or more access points. Each access point acts like a traditional network bridge.
One problem which has prevented wider use of WLANs was the inadequate standardization for a long time. This situation has now changed with an increasing tempo since the Institution of Electrical and Electronics Engineering (IEEE) has adopted WLAN Standards in recent years. See e.g., Publication XP002206839, IEEE standard for information technology telecommunication and information exchange between systems—local and metropolitan area networks—specific requirement, Part II: wireless LAN medium access control (MAC) and physical layer (PHY) specification, (ISO/IEC 8802-11, ANSI/IEEE Std. 802.11-1999), 20 Aug. 1999.
One such disadvantage was also that wireless networks did not allow such high data transmission rates as wire-based networks.
This was because the bandwidths provided by the regulators are limited and wireless networks have to introduce additional security mechanisms and expanded information in the data packets in order to make it possible to take account of the characteristic of a radio link.
Since radio links are more susceptible to interference than cables, additional correction mechanisms have been introduced in the MAC layer in Standard 802.11.
In the event of data transmission errors, these correction mechanisms ensure that the data packets are sent again, without any involvement of higher protocol layers in this process. This may now possibly lead to lengthened data transmission times in comparison to the quite error-free connection in a cable-based network.
The IEEE Committee continued the further development of the already established WLAN Standard 802.11 by supplementing 802.11a for 5 Ghz and 802.11b for 2.4 Ghz.
At the moment, a further increase in the data rate in the 2.4 Ghz band is being worked on in the IEEE 802.11g working group. One important feature of the new standard is the backwards compatibility with the established IEEE 802.11b Standard.
The provider companies found out quite quickly that lack of compatibility detracts from the acceptance of their products for wireless local area network technology.
In order to allow matching to different radio channels, the 802.11 Standard and its extensions 802.11a and b allow various data transmission rates. The data rates are coded in an information element which, in accordance with IEEE 802.11, allows a maximum number of 8 rates and is transmitted in the beacon signal.
The IEEE 802.11g Standard provides for more than 8 data rates to be allowed. Intraoperability tests have shown that, when more than 8 data rates are notified in the conventional information element, backwards compatibility with existing solutions is no longer guaranteed.
Consideration is now being given to improving communication devices and network data transmission methods. In particular attention is directed to communication devices and data transmission methods which can achieve a wide range of data transmission rates while remaining fully compatible with communicants operating in diverse modes including legacy modes.